JPH0794444B2 - Method for improving the quality of 2,4-imidazolidinone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is important as a raw material for amino acids, pharmaceuticals and agricultural chemicals.
The present invention relates to a method for improving the quality of 2,4-imidazolidinedione.

[Conventional technology and its problems]

Conventionally, 2,4-imidazolidinedione is produced by using glyoxal or glyoxylic acid and urea, glycine and cyanate, glycolonitrile and ammonium bicarbonate, and glycinonitrile and ammonium bicarbonate as raw materials.

For the production of the 2,4-imidazolidinedione, a method using glycolonitrile is advantageous in view of easy availability of raw materials and economy, but glycolonitrile is unstable, and this decomposition is a reaction product. However, there is a problem in that it causes a decrease in purity and causes coloring.

The present inventors have found a method for solving this problem by limiting the molar ratio of ammonia and carbon dioxide in the reaction system and the concentration of glycolonitrile (JP-A-61-83164). However, this method is not efficient because the concentration is limited, and when the concentration is increased, coloring becomes remarkable, which is not preferable in terms of quality. Further, the colored reaction solution can be treated with activated carbon, an ion exchange resin or the like for improvement, but it is economically disadvantageous because the cost for purification is high.

An object of the present invention is to provide a good quality 2,4-imidazolidinedione without using such activated carbon and ion exchange resin.

[Means for Solving the Problems]

In order to achieve the above object, the present inventors have conducted various studies on methods for solving such problems, and by reacting glycolonitrile with carbon dioxide and ammonia using water as a reaction solvent, 2,4-imidazo. In the method for producing lysinedione, by adding glycolic acid to the starting material glycolonitrile and blowing a sulfite gas into the reaction solution, or by allowing a sulfite or an acid sulfite to be present, the color of the reaction solution is significantly improved. Then, they have found that the quality of the product is improved, and have completed the present invention.

That is, the present invention provides a method for producing 2,4-imidazolidinedione by reacting ammonium bicarbonate, ammonium carbonate or ammonia with carbon dioxide or a mixture thereof with glycolonitrile, wherein (a) glycolonitrile is added to glycol A method for improving the quality of 2,4-imidazolidinedione, which comprises adding an acid and allowing sulfurous acid gas, sulfite or acid sulfite to be present in the reaction system (b).

Next, the present invention will be described in more detail. The method for improving the quality of 2,4-imidazolidinedione of the present invention is
Blow a predetermined amount of sulfurous acid gas into an aqueous solution containing ammonium bicarbonate and ammonia or carbon dioxide gas and ammonia, or
Sulfite or acidic sulfite is added, and glycolonitrile preliminarily added with a predetermined amount of glycolic acid is supplied and reacted in a sealed state.

After completion of the reaction, the mixture is concentrated, treated with sulfuric acid, further concentrated and cooled, and the resulting white crystals are filtered off to obtain 2,4-imidazolidinedione.

The glycolonitrile used in the present invention may be, for example, a 50% by weight aqueous glycolonitrile solution. This aqueous solution is obtained by reacting formalin and hydrocyanic acid, but is used in a state where unreacted hydrocyanic acid is removed. Alternatively, a small amount of sulfuric acid may be added to stabilize the solution.

The quality of glycolic acid added to this glycolonitrile aqueous solution is not particularly limited and may be industrial grade. Further, although the action of glycolic acid on the aqueous solution of glycolonitrile is unknown, it is considered that the decomposition of the raw material glycolonitrile is suppressed by chelating a metal contained in a small amount in the aqueous solution of glycolonitrile.

There are no particular restrictions on ammonium bicarbonate and ammonia or carbon dioxide and ammonia, but a combination of carbon dioxide, an aqueous ammonia solution, and liquid ammonium is preferable in consideration of water balance.

The sulfite gas, sulfite or acidic sulfite present in the reaction system is not particularly limited, but is inexpensive and easy to handle, alkali metal sulfite or acidic sulfite, for example, sodium sulfite, potassium sulfite, acidic sulfite. Sodium and potassium acid sulfite are preferred. When sulfurous acid gas is used, ammonia is present during the reaction so that ammonium sulfite is substantially produced and the effect is exhibited.

The amount of glycolic acid added may be 0.001 mol or more, preferably 0.1 to 5.0 mol, based on 1 mol of glycolonitrile as a raw material.

The amount of sulfurous acid gas, sulfite or acidic sulfite added may be 0.001 mol or more, preferably 0.1 to 2.0 mol, per mol of glycolonitrile.

Further, the reaction may be either a batch system or a continuous system. The reaction is
It is preferably carried out under closed pressure, and the reaction temperature is usually 60 to
The temperature is 150 ° C, preferably 80 to 120 ° C.

The reaction time varies depending on the reaction temperature, but is usually in the range of 0.25 to 5 hours.

After the reaction, the resulting product is treated with an acid such as sulfuric acid or hydrochloric acid to obtain an acid concentration.
Add 10 to 30% by weight, temperature 70 to 100 ℃, 2
The acid treatment such as stirring for ˜3 hours can be performed to cyclize 2,4-imidazolidinedioic acid and 2,4-imidazolidinedioic acid amide into 2,4-imidazolidinedione.

〔Example〕

Next, representative examples of the method of the present invention will be shown and described in more detail, but these are merely examples for explanation, and the present invention is not limited to these examples.

In addition, the measurement of chromaticity in Examples and Comparative Examples was performed by the following method.

After dissolving added platinum potassium chloride (K ₂ PtCl ₆₎ 2.49g, crystalline cobalt chloride _{(CoCl 2 · 6H 2 0)} 2.0g and concentrated hydrochloric acid 200 ml, and diluted to 1 with water. Using a colorimeter to measure this liquid,
The absorbance at 370 mμ was measured and the chromaticity was set to 1000,
A chromaticity of 100 was obtained by diluting this solution 10 times.

Example 1 In a pressure resistant reactor made of glass equipped with a stirrer and a thermometer and having an internal capacity of 1000 ml, 166.6 g of ammonium bicarbonate, 52.4 g of 28% by weight aqueous ammonia solution, 481.0 g of pure water and 0.7 of sodium sulfite were prepared.
g was charged and heated to 100 ° C. When the temperature reached 100 ° C, 110.0 g of a 50% by weight glycolonitrile aqueous solution to which 2.2 g of glycolic acid had been added was charged for 1 hour, and then 1
After reacting for a period of time and concentrating to 40% by weight of the reaction mixture under reduced pressure (chromaticity 694), 95% by weight sulfuric acid was added to the sulfuric acid concentration of 15%
And acid treatment was carried out at 90 ° C. for 3 hours (the chromaticity of the liquid after the acid treatment was 298) and then filtered to obtain 75.3 g of white 2,4-imidazolidinedione.

Example 2 The same operation as in Example 1 was carried out except that 0.9 g of potassium sulfite was added instead of 0.7 g of sodium sulfite. The chromaticity of the solution after acid treatment is 306, and the white 2,4-imidazolidinedione
75.4 g was obtained.

Example 3 Acidic sodium sulfite instead of 0.7 g of sodium sulfite
The same operation as in Example 1 was performed except that 0.6 g was added. The chromaticity of the solution after the acid treatment was 316, and 75.2 g of white 2,4-imidazolidinedione was obtained.

Example 4 The same operation as in Example 1 was carried out except that 125 ml of sulfurous acid gas was added instead of 0.7 g of sodium sulfite. The chromaticity of the solution after acid treatment is 301, and the white 2,4-imidazolidinedione 7
4.3 g was obtained.

Example 5 The same operation as in Example 1 was performed except that the amount of sodium sulfite added, 0.7 g, was increased to 1.4 g. The chromaticity of the liquid after acid treatment is 184
Thus, 75.5 g of white 2,4-imidazolidinedione was obtained.

Comparative Example 1 Using the same equipment as in Example 1, ammonium bicarbonate 166.6
g, 28% by weight aqueous ammonia solution 52.4 g and pure water 481.0 g were charged and heated to 100 ° C. 50% by weight at 100 ℃
110.0 g of an aqueous glycolonitrile solution was charged in 1 hour. After charging, the reaction was carried out for 1 hour, and 95% by weight sulfuric acid was added to a solution (chromaticity 1655) concentrated to 40% by weight of the reaction solution under reduced pressure so that the sulfuric acid concentration became 15% by weight, and the mixture was stirred at 90 ° C for 3 hours. Acid treatment was carried out for a time (the chromaticity of the liquid after the acid treatment was 1037),
69.5 g of the yellow 2,4-imidazolidinedione were obtained.

〔The invention's effect〕

The quality improvement method of the present invention is 184 / 1037-316 / 10 in terms of chromaticity ratio from the examples / comparative examples without using activated carbon, in-exchange resin or the like.
It is possible to improve the coloring of 37 and obtain a white, good quality 2,4-imidazolidinedione. Further, it is industrially useful because no purification step is required.

Claims (1)

[Claims] 1. A method for producing 2,4-imidazolidinedione by reacting ammonium bicarbonate, ammonium carbonate or ammonia with carbon dioxide or a mixture thereof with glycolonitrile, wherein (a) glycolonitrile is added with glycolic acid. And (b) allowing sulfite gas, sulfite or acid sulfite to be present in the reaction system, a method for improving the quality of 2,4-imidazolidinedione.